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A Study of Rickettsia tsutsugamushi in Russia.

Research Project

Project/Area Number 05044190
Research Category

Grant-in-Aid for international Scientific Research

Allocation TypeSingle-year Grants
SectionJoint Research
Research InstitutionNiigata College of Pharmacy

Principal Investigator

TAMURA Akira  Niigata College of Pharmacy, Professor, 薬学部, 教授 (50027314)

Co-Investigator(Kenkyū-buntansha) BALAYEVA N.m.  Russia Medical Academy, Chief Investigator, ガマレア研究所, 主任研究員
TARASEVICH I.v.  Russia Medical Academy, Professor, ガマレア研究所, 教授
URAKAMI Hiroshi  Niigata College of Pharmacy, Assiciate Professor, 薬学部, 助教授 (80139732)
KADOSAKA Teruki  Aichi Medical University, Assistant, 医学部, 助手 (90109760)
金子 清俊  愛知医科大学, 医学部, 教授 (00013904)
Project Period (FY) 1993 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 1994: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1993: ¥2,600,000 (Direct Cost: ¥2,600,000)
KeywordsSurub typhus / Rickettsia tsutsugamushi / Trombiculid mites / Rodents / Vector / Isolation of phogens / Far East Russia / Infection rate
Research Abstract

For the ecological and epidemiological study of tsutsugamushi disease in the Fdr East Russia, we attempted to isolate Rickettsia tsutsugamushi from trombiculid mites and wild rodents which were collected on the field near Vladivostok. The spleens, livers and sera of 278 rodents were frozen in liquid nitrogen immediately after dissection, and the frozen samples in a dryice jar were carried back to Japan. By immunofluorescence test, antirickettsial antibodies were found only in 4 rodents : two positive and two puedopositive.The organs from these four rodents and 21 others captured in the same areas were used for rickettsial isolation. On the other hand, 12,600 engorged mites were harvested from the rodents, and the alive mites were also used for rickettsial isolation after identification of the species. The homogenates of mites and the organs of rodents were inoculated to L or Vero cell cultures, or mice treated with or without immunosuppressive agent. In our experience, these cells and mice are adequate for isolation of both virulent and avirulent rickettsiae. The cells were kept for two months by exchanging occasionally the culture medium, and spleen-homogenates of the inoculated mice were blind-passaged twice to other mice. However, rickettsiae were isolated in neither cell cultures nor mice. Furthermore anti-rickettsial antibody did not rise in the inoculated mice. These results indicated that very few mites and rodents in the Far East Russia were infected with R.tsutsugamushi at present. However, Tarasevich, a coworker of this study, reported that the rodents and mites in this region were heavily infected in 1960s and rickettsiae were easily isolated from these animals. These lines of evidence suggest that rickettsial infection in the trombiculid mites decreased markedly during a few decades. An interesting and important question on the reason of these dramatic change is remained for further studies

Report

(2 results)
  • 1994 Final Research Report Summary
  • 1993 Annual Research Report
  • Research Products

    (5 results)

All Other

All Publications (5 results)

  • [Publications] Kadosaka,T.,Tamura,A.,and Tarasevich,I.V.: "New species of Neotrombicula(Acari:Trom biculidae)from southern Primoryeterritory,Russia Far East." J.Med.Entomol.(in press). (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Kadosaka, T., Tamura, A., and Tarasevich, I.V.: "J.Med.Entomol." New species of Neotrombicula (Acari : Trombiculidae) from southern Primorye territory, Russia Far East.(in press). (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] H.Urakami,M.Takahashi,E.Hori,A.Tamura: "An ultrastructural study of vertical transmission of Rickettsia tsutsugamushi in the oogenesis in Leptotrombidium pallidum." Am.J.Trop.Med.Hyg.50. 219-228 (1994)

    • Related Report
      1993 Annual Research Report
  • [Publications] 角坂照貴、金子清俊、浦上弘、多村憲、F.N.Shubin、G.P.Somov、I.V.Tarasevich: "ロシア極東地域におけるツツガムシ" 衛生動物. (印刷中). (1994)

    • Related Report
      1993 Annual Research Report
  • [Publications] H.Urakami,M.Takahashi,M.Murata,A.Tamura: "An electron microscopic study of the distribution and vertical transmission of Rickettsia tsutsugamushi in Leptotrombidium pallidum." Jpn.J.Med.Sci.Biol.(発表予定). (1994)

    • Related Report
      1993 Annual Research Report

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Published: 1993-04-01   Modified: 2016-04-21  

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